The invention relates to a process for treating the edges of a saw-tooth wire for clothings in textile machines and to an apparatus for carrying out the method.
It is already known to use saw-tooth wire clothings the teeth of which are rounded off, in order to achieve a better carding performance and to avoid clogging of the clothing.
In a known process, the rounding off is achieved by means of chemical or electrochemical deburring (DE-OS No. 33 32 804). However, the duration of the treatment proved to be very critical. If the treatment was extended over too long a period, the edges of the teeth developed so-called snowdrifts or knobbles, i.e. lateral projections on the teeth. Such disadvantageous surface irregularities occurred especially when the saw-tooth wire had been tempered prior to the chemical treatment, for instance by hardening and annealing. However, tempered saw-tooth wires call for a longer treatment, which in turn aggravates the aforementioned phenomenon.
It has been tried to reduce the duration of the treatment by adding certain salts such as those containing ammonium fluoride or producing hydrogen peroxide, which, however, resulted in the occurrence of pits, particularly in the area of the base of the teeth, but also on the side faces of the same.